Single cell vertical static flow flotation unit cross-reference to related applications

ABSTRACT

The invention relates to a new and improved apparatus for removing suspended matter from liquid. The apparatus has a single cell vertical cylindrical hydraulic flotation vessel which is provided with a separation wall to separate a lower gasification chamber from a middle degasification chamber and an upper gas chamber. A number of alternative arrangements are provided for controlling skim collection through controlling volume of liquid within the vessel and changing the volume of liquid through the use of adjustable timer which intermittently send signals to outlet valves of the skim collection outlet or of the treated liquid outlet. 
     The invention provides for alternative arrangement of introducing liquid into the vessel, so as to achieve more intimate mixing of gas and liquid introduced into the vessel.

Cross-Reference to Related Applications

This is a continuation of application Ser. No. 384,833 filed July 25,1989 now U.S. Pat. No. 5,011,597 which is a continuation-in-part ofco-pending U.S. patent application Ser. No. 255,505 filed Oct. 11, 1988,(now abandoned) entitled "Induced Static Flotation Cell", the disclosureof which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for removingsuspended matter from liquid. The method and apparatus of the presentinvention have utility, for example, in separating suspendedcontaminants and/or oil from water.

Even more specifically, the present invention relates to a method andapparatus, wherein small bubbles created by the air injection into themain body of liquid attach themselves to the particles or droplets ofcontaminants to be removed and provide buoyancy to raise them to thesurface of the liquid. The froth created on the surface of the liquid isremoved from the surface, while heavy clean liquid remains below thefroth level.

In many industries, including oil, paper and pulp, textile, electricitygenerating and food processing, there is an ever present problem ofcontaminated water as a by-product of various processes. In particular,water is often used to aid in the production of oil and gas on offshoreplatforms. This water is usually pumped into a formation in order topump oil out. As a result, the water becomes contaminated with oil andsolids encountered in the formation, and therefore, cannot be disposedof simply by dumping it into the surrounding water. Accordingly,numerous methods and systems have been devised to reduce the contaminantcontent in this water to a level which allows discharge of the waterinto the sea.

One such apparatus is disclosed in U.S. Pat. No. 4,782,789 issued onNov. 8, 1988 for "Induced Static Flotation Cell". The device inaccordance with '789 patent uses a plurality of gasification chamberswhich are sequentially, horizontally arranged for gradual separation ofcontaminants from water through mixing it with air bubbles which carrythe contaminant laden froth to the top of the chambers for removaltherefrom.

However, under certain conditions, especially wherein the space isrestricted, it is impossible to utilize a horizontally arrangedmulti-cell unit. Additionally, a careful balancing of gas flow andliquid flow is required in order for the unit to successfully separatecontaminants from water.

Another system of flotation separator is disclosed in U.S. Pat. No.4,094,783 issued on June 13, 1978 for "Centrifugal Flotation Separator".The system, in accordance with '783 patent, shows the use of a circular,cylindrical vessel with a horizontal tray positioned inside the vesselnear the top, with the tray having an axial opening. Air under pressureis introduced into the vessel from the top of the vessel, whilecontaminated fluid is introduced through a tangential pipe, underpressure, at a level below the tray.

However, there is a disadvantage of introducing air from the top of thevessel, since some portions of the contaminated liquid may escape mixingwith air and merely settle on the bottom of the vessel, thusconsiderably reducing the quality of skim separation.

The present invention contemplates elimination of the above drawbacksassociated with the known devices.

SUMMARY OF THE INVENTION

The present invention achieves its objects and overcomes shortcomings ofthe prior art in a simple and straightforward manner. A substantiallycylindrical, vertically oriented vessel is provided, said vessel havinga closure at the bottom and the top. An interior chamber formed withinthe vessel is divided by an annular separation wall. The separation walldivides a lower gasification chamber from a middle degasificationchamber and an upper gas chamber. The separation wall has a concaveshape with a central opening, from which a funnel or conduit extendsupwardly through the degasification chamber and terminates a distancebelow a conduit serving as a skim collection outlet. The liquid to betreated is introduced into the vessel through one or more liquiddistribution lines. A primary distribution line provides for the use ofat least one distribution header having an outlet adjacent a bottom ofthe vessel for introducing the liquid having suspended matter thereininto the vessel. In the alternative, in addition to the primary, asecondary liquid distribution system can be used which allows forintimate mixing of the liquid with a gas flow which is introduced intothe vessel by an eductor means having an outlet inside the interiorchamber slightly above the outlet of the primary liquid distributionsystem. When a second alternative method is used, the flow of liquidinto the vessel is controlled by a pressure controller through athree-way pressure control valve which diverts any excess liquid to theprimary liquid distribution outlet, bypassing the secondary liquiddistribution line. A liquid recirculation line which connects the bottomof the degasification chamber with the liquid inlet line is providedwith a normally closed check valve which is mounted upstream from apoint of connection of recirculation line and the inlet line. The checkvalve opens when pressure in the recirculation line less than thepressure in the main liquid inlet line is detected.

A gas recirculation line fluidly connects a gas chamber in the uppermostportion of the vessel with a gas eductor means which introduces gas atthe bottom of the vessel to achieve better mixing of the liquiddelivered into the vessel with the gas. Mounted within the gas eductorline, substantially coaxially therewith, is an outlet of the secondaryliquid distribution line.

A number of alternative arrangements to control skim collection areprovided in accordance with the present invention. In accordance withthe first arrangement, a liquid level controller positioned in the upperportion of the vessel transmits a signal to a control valve which ismounted at the outlet for removing the treated liquid from the vessel.An adjustable timer interrupts a signal from the liquid levelcontroller, so as to close the valve and cause the volume of liquidwithin the vessel to increase, thus raising the level of liquid andallowing the froth which has been carried to an uppermost portion of thevessel by gas bubbles to spill over the edge of the skim collectionfunnel and be removed from the vessel through a skim collection outlet.In accordance with a second alternative arrangement, the means forcontrolling skim collection volume are provided with a normally opentreated liquid outlet valve, an adjustable timer which is connected tothat valve and a vertically adjustable nozzle which is set to allow apredetermined volume of liquid to exit the vessel. Depending on theamount of suspended contaminants in the liquid introduced into thevessel, the timer is set to intermittently close the valve at the outletfor the treated liquid, allowing the volume in the vessel to increase,the level of liquid to rise, causing the froth to spill over the edge ofthe skim collection funnel and to exit from the vessel. In accordancewith a still further arrangement, the means for controlling skimcollection volume comprise a liquid level controller which is connectedto an upper portion of the vessel, a treated liquid outlet control valvewhich is operatively connected to receive a signal from the liquid levelcontroller, an adjustable timer and a skim collection outlet valve whichopens in response to an intermittent signal received from the timer.Since the skim outlet valve is normally closed, the froth is allowed tocollect in the upper portion of the vessel above the skim collectionfunnel. When the timer opens the skim collection outlet valve, the frothis allowed to exit through the skim outlet means.

Still, further means for controlling skim collection volume comprise anormally closed skim collection outlet valve, an adjustable timeroperatively connected to the skim collection outlet valve and adapted tosend intermittent signals to the valve, causing the valve to open andallow outlet of the froth which has collected above the skim collectionfunnel from the vessel. A vertically adjustable nozzle which isconnected to the treated liquid outlet is preset to maintain apredetermined volume of liquid in the vessel by allowing a predeterminedflow of liquid to exit the vessel.

It is, therefore, an object of the present invention to provide animproved apparatus for removing suspended matter from a liquid.

It is a further object of the present invention to provide a single cellvertical flotation apparatus for removing suspended matter from aliquid.

It is still a further object of the present invention to provide anapparatus having alternative ways of controlling skim collection volumefrom the vessel.

It is still a further object of the present invention to provide analternative method for intimate mixing of the liquid having suspendedmatter therein with gas injected into the vessel.

It is still a further object of the present invention to provide anapparatus having better gas distribution and improved efficiency of skimcollecting.

These and other objects of the invention will be more apparent from thefollowing detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For further understanding of the nature, objects and advantages of thepresent invention, reference will be had to the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich like parts are given like reference numerals, and wherein:

FIG. 1 is a schematic view of the preferred embodiment of the apparatusof the present invention;

FIG. 2 illustrates one of the alternative methods of controlling skimconcentration;

FIG. 3 is a schematic view showing another alternative method ofcontrolling skim concentration;

FIG. 4 is a schematic view showing still another alternative method ofcontrolling skim concentration, and;

FIG. 5 is a schematic view illustrating still further alternative methodof controlling skim concentration;

FIG. 6 is a schematic view of the preferred embodiment of the presentinvention showing an alternative influent method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described, by way of example, and notlimitation, with the inflow being water contaminated with oil and othersuspended particles. It is to be understood that the present inventionhas utility in numerous applications in which it is desirable toseparate suspended matter and/or oil from a liquid, and that thesuspended matter, the liquid, or both may be a desired product of theprocess.

The preferred embodiment of the apparatus of the present inventioncomprises a substantially cylindrical, vertically oriented vessel 10having a continuous cylindrical sidewall 12, bottom 14 and dome top 16.Extending through the bottom 14 is one or more liquid inlet distributionlines 18, extending through the bottom 14 into an interior chamber 20formed by the sidewall 12, bottom 14 and dome top 16. The line(s) 18 istopped by a distribution header 22 which extends perpendicularly to aconduit formed by the line 18 and has a plurality of openings 24therein, allowing introduction of untreated, solids laden with oil,water into the chamber 20.

A gas inlet means 26 in the form of an eductor which extends through thebottom 14 into the chamber 20 introduces gas into the chamber 20.

An annular shoulder flange 32 extends perpendicularly to a vertical axisof the gas inlet conduit 30.

A striker plate 34 is mounted a distance above the shoulder 32 insubstantially parallel relationship to the shoulder 32 andperpendicularly to the vertical axis of the conduit 30. A gas outletslot 36 is formed between the striker plate and the shoulder 32,allowing escape of the injected gas into the chamber 20. The slot 36 ispositioned at a vertical level slightly above the level of liquid inletopenings 24.

As can be seen, the gas introduced through the gas conduit 30 is forcedto exit at a 90 degree angle into the chamber 20. The high energy ofimpact and the perpendicular change of direction causes the gas to formmicroscopic bubbles as the gas exits through the slot 36. Immediately,upon exiting into the chamber 20, the gas mixes with the water at thebottom level of the vessel 10, such that the contaminants and allparticles coat the gas bubbles and are carried upwardly towards the topof the gasification chamber 40 which forms a part of the interiorchamber 20.

The gasification chamber 40 is separated from the remainder of thevessel by an annular separation concave plate 42, which is attachedabout its circumferential edge to the side wall 12. An opening 44 iscentrally formed in the separation plate 42 and a gas conduit 46 extendsin circumferential relationship to the opening 44, allowing the froth tomove upwardly, in a more concentrated state towards the top of thevessel 10. The liquid and froth is forced through the gas conduit 46 bythe pressure in chamber 40. Due to the differences in the specificgravity of the fluid and froth, the froth, having the lighter specificgravity, flows up to the annular space 56 and is collected in chamber54. The liquid with the heavier specific gravity flows to the bottom ofdegasification chamber 50 for discharge through outlet 48.

A skim funnel 52 is mounted in the top portion of the degasificationchamber 50, separating the degasification chamber 50 from the uppermostgas chamber 54. The skim funnel 52 is smaller in diameter than thediameter of the vessel side wall 12, leaving an annular space 56 betweenthe side wall 12 and an upwardly extending rim 58 of the skim funnel 52.The skim funnel 52 is provided with a central opening 57 from which skimoutlet 60 extends first vertically downward and then turninghorizontally at 90 degrees to exit the vessel 10.

A portion of treated degassed water which settled on the bottom ofchamber 50 leaves the vessel 10 through water recirculation line 49 toenter the vessel 10 again through the suction of an eductor pump 70 andthrough the gas/water eductor valve 72 to eductor 26, and morespecifically to liquid inlet nozzle 28, wherein it is mixed with gas andintroduced again into the gasification chamber 40 of the vessel 10.

Valve 72 is designed to adjust water flow into the vessel 10, which inturn regulates gas recirculation flow.

In the top of the vessel 10, a gas chamber 54 is formed in fluidcommunication with a gas recirculation line 74 which connects the top ofthe vessel 10 with an eductor or gas inlet means 26, recirculating thegas which was released from the bubbles carried to the upper portion ofchamber 50. The gas recirculated through the line 74 is mixed with waterof the line 49 which is supplied through the line 74 into therecirculated liquid nozzle 28 and, mixing with gas, is reintroduced intothe vessel 10 through the slot 36.

In operation, the contaminated and/or solid laden oily water isreintroduced into the vessel 10 by inlet lines 18 and through theopenings 24. The gas is introduced through the eductor or gas inletmeans 26 and, mixed with water supplied through the nozzle 28 exits theinlet means through the slot 36, initiating the gasification process inthe gasification chamber 40, while the solids and oily particles adhereto gas bubbles and are carried upward towards the top of the chamber 40,wherein the froth is concentrated by forcing the froth through theconduit 44 having a substantially reduced diameter in comparison withthe diameter of the vessel 10. The concentrated froth exists thegasification chamber 40 and is carried further upwardly to the top ofthe degasification chamber 50. The froth concentrates in the annulus 56formed between the wall 12 and the flange 58 of the concentric funnel52. The water, having a specific gravity higher than the froth, settlesby gravity in the bottom of the chamber 50 and is withdrawn therefromthrough the water outlet 48 and through the water recirculation line 49.The gas released through the breaking of bubbles in the froth travelsfurther upward into the gas collection chamber 54 and exits the vesselthrough recirculation line 74. The froth is removed from the funnel 52,where it flows by overflowing the top edge of the flange 58 and iswithdrawn from the vessel through the opening 57 and skim outlet line60.

In order to facilitate separation of water from gas and oily solids,adequate retention time is allowed for the fluid carried into thechamber 50, so as to utilize the difference in specific gravity betweenheavy water and lighter coalesced oil froth to form two distinct layers.

Reference will now be made to FIG. 2, wherein one of the alternativemethods of controlling skim collection is illustrated. A liquid levelcontroller 80 is located in the uppermost section of the vessel 10 andis adjusted to control the level of liquid within the vessel 10 slightlybelow the upper edge of the flange 58 of the skim collection funnel 52by sending a control signal through a three-way solenoid valve 82 to theoutlet control valve 84 which is positioned at the treated water outlet48. An adjustable timer 86 connected to the valve 82 interrupts thecontrol signal from the liquid level controller 80, causing controlvalve 84 to close or throttle to a reduced opening for a predeterminedperiod of time of closure. This causes the level of liquid within thevessel 10 to rise and spill the oily froth and suspended solidscollected at the surface over the edge of the flange 58 into the frothcollection funnel 52 and exit the vessel by way of skim outlet 60.

Referring now to FIG. 3, a further alternative method of skim removalwill be discussed. As can be seen in FIG. 3, there is provided a headchamber 90 on the uppermost portion of the vessel 10.

A vertically adjustable nozzle 92 is adjusted to control the level ofliquid within the vessel 10 slightly below the upper edge of the flange58 of the skim collection funnel 52. Treated water flows over the topedge of the vertically adjustable nozzle 92 and exits the head chamber90 through the head chamber outlet conduit 94 and its outlet opening 96.The outlet valve 84 of the treated water outlet 48 is normally openduring operation, allowing the treated water to exit the vessel 10. Apreset adjustable timer 98 is operationally connected to the valve 84through conventional means. When the timer 98 activates, the outletvalve 84 is closed or throttles, causing the liquid level to rise andspill the oily froth and suspended solids collected at the surface intothe collection funnel 52 and to exit the vessel 10 through the skimoutlet conduit 60.

FIG. 4 illustrates still another alternative method to control skimcollection within the vessel 10. A liquid level controller 80 which issimilar to the liquid level controller of FIG. 2 is positioned in theuppermost section of vessel 10 and is adjusted to maintain the liquidlevel slightly above the upper edge of the skim collection funnel 52. Itis accomplished by sending a control signal to the normally closedoutlet control valve 84. The outlet control valve 84 is connected byconventional signal transmitting means to the liquid level controller80. The skim collection outlet 60 is provided with a skim control valve100. The valve 100 is operationally connected to a timer 102 which isadjusted to send pulses at predetermined periods of time to the valve100.

When it is necessary to discharge the collected oily froth and suspendedsolids which have been pushed upwardly to the quiescent zone above theskim funnel 52, the adjustable timer 102 pulses the skim outlet valve100, causing it to open for an adjustable period and duration of time,thus allowing skimming without interruption of the outlet flow throughthe valve 84.

Referring now to FIG. 5, a still further alternative method of skimmingthe froth is illustrated. In the embodiment of FIG. 5, some features ofthe embodiments of FIG. 3 and FIGS. 4 are utilized. Such, a timer 102 isoperationally connected to the skim outlet valve 100. A head chamber 90is located on the uppermost section of the vessel 10. The head chamber90 is fluidly connected to the uppermost portion of the vessel 10through a conduit 91. A vertically adjustable nozzle 92 has its outletwithin the head chamber 90, and an outlet line 94 has its inlet withinthe head chamber 90, with the outlet of the line 94 being designated bynumeral 96. The vertically adjustable nozzle 92 is adjusted to maintainliquid level in vessel 10 slightly above the upper edge of the skimcollection funnel 52. Treated water enters through the outlet 48 andflows through the conduit 91 into the head chamber 90 through the nozzle92. The treated water subsequently exits the head chamber 90 through theoutlet line 94 and ultimate outlet 96.

Meanwhile, oily froth and suspended solids are forced upward to thequiescent area above skim funnel 52. This collection of oily froth andsuspended solids is discharged from the vessel 10 through skim outletline 60 and normally closed skim valve 100. The adjustable timer 102pulses the skim valve 100 open for an adjustable interval, thuspermitting skimming without interrupting outlet flow of treated waterthrough the outlet conduit 91, into the head chamber 90 and into theultimate treated liquid outlet 96.

The volume of skim collection is therefore controlled by controlling theflow of treated liquid from the vessel. Normally, as illustrated in FIG.5, the volume of fluid in the vessel is adjusted to retain the level offluid slightly above the edge of the skim collection funnel 52.

Referring now to FIG. 6, the apparatus of the present invention isillustrated as having alternate means for introducing contaminated fluidinto the vessel 10. The water to be treated, which contains oilparticles and suspended solids enters line 110 and flows through theeductor pump 70 and three-way pressure control valve 106 into the nozzle28 (which forms a part of the secondary liquid distribution means). Apressure controller 108 adjusts the three-way valve 106 (or any othersuitable means of bypassing) to maintain proper pressure on the nozzle28. Any excess water is diverted by the three-way valve 106 to theprimary contaminated liquid inlet line 18 which is located on the bottomof the vessel 10 and from then onto the distribution header(s) 22 whichare located adjacent to and below the eductor assembly or gas inletmeans 26. When the head pressure in water circulation line 49 is greaterthan the supply pressure in the inlet line 110, a check valve 112,positioned in the water circulation line 49, opens to providesupplemental eductor water to the suction of eductor pump 70. The checkvalve 112 is positioned between the inlet of the line 49 from thechamber 50 and the pump 70. When the pressure at inlet connection 110 isgreater than the head pressure in water circulation line 49, thenormally opened check valve 112 closes to prevent influent water fromcontaminating the water in degasification chamber 50. In this manner,more effective intimate mixing of influent oily water and suspendedsolids is achieved. An added advantage of this alternate method is thatthe water volume which is removed from the degasification chamber 50 isreduced or completely eliminated, thus increasing the retention time ofwater in degasification chamber 50 and improving efficiency of thevessel by increasing the retention time. This alternate inletarrangement can be used with any of the skim collection methods whichhave been illustrated and discussed above.

From the foregoing description, it will be appreciated that an improvedapparatus and method of separating water from contaminants is disclosed.The single gas eductor mechanism requires no complex balancing, as thecase would have been with multiple cells. A single skimmer arrangementalso allows to avoid balancing of individual levels within variousmultiple cells. The skim volumes of less than one percent (1%) to threepercent (3%) can be easily achieved utilizing the apparatus and methodof the present invention. The concentration of oil and solids in skimmedfroth which reaches the skim collection funnel is greater, thus allowingto substantially reduce the volume of waste which has to be handled bythe users. The vertical cylindrical shape of the vessel permits bettergas distribution and improved efficiency in comparison with othergeometric configurations. Additionally, an improved method of achievingintimate mixing of gas and water is disclosed herein.

While a number of embodiments of the present invention have beendescribed herein, it is to be understood that various modifications canbe made thereto without departing from the spirit and scope of thepresent invention. I therefore, pray that my rights to the presentinvention be limited only by the following claims.

I claim:
 1. An apparatus for removing suspended matter from a liquid, comprising:a substantially cylindrical vertically oriented vessel having a convex down bottom a concave down closed top and a continuous side wall forming an interior chamber adapted to receive a flow of liquid having suspended matter therein; said vessel having a vertical axis; an annular separation wall means having an opening therein and being mounted in the vessel transversely to the vertical axis of the vessel for separating a lower gasification chamber from the remainder of the interior chamber; a degasification chamber formed above said separation wall means in fluid communication with the gasification chamber through the opening; means for introducing the flow of liquid into the gasification chamber; means for introducing a flow of gas into the gasification chamber for attracting the suspended matter and for carrying the suspended matter upwardly to an upper portion of the vessel; means for concentrating the suspended matter extending vertically through at least a portion of the degasification chamber; a skim collection means for collecting the suspended matter in the upper portion of the vessel and delivering the skim outside the vessel, said skim collection means being positioned at a level above said suspended matter concentrating means; means for removing treated liquid from the vessel positioned in a lower part of the degasification chamber; treated water recirculation means fluidly connecting the degasification chamber with said liquid flow introducing means for facilitating introduction of the gas flow from said means for introducing said flow of gas into the gasification chamber; and a means for controlling a volume of skim collection by changing a volume of liquid in the vessel at predetermined intervals.
 2. The apparatus of claim 1, wherein said means for controlling skim collection volume comprise a liquid level controller means operatively connected with the upper portion of the vessel and having means for transmitting a signal to a control valve means, said control valve means being operatively connected to the means for removing treated liquid from the vessel, and an adjustable timer means connected to the valve means for intermittently interrupting said signal from said liquid level controller means to slightly increase said volume of liquid contained within the vessel by throttling or closing said control valve means, so as to raise a level of liquid and allowing skimming through said skim collection means.
 3. The apparatus of claim 1, wherein said means for controlling skim collection volume .comprise a normally open treated liquid outlet valve means, an adjustable timer means operatively connected to said valve means and said timer means having means to send an intermittent signal to said valve means causing said valve means to close, and a vertically adjustable nozzle means connected to said treated liquid outlet means and said nozzle means acts to maintain a predetermined volume of liquid in the vessel.
 4. The apparatus of claim 1, wherein said means for controlling skim, collection volume comprises a liquid level controller means operatively connected with the upper portion of the vessel and having means for transmitting a signal, a treated liquid outlet control valve means operatively connected to receive said signal from said liquid level controller means, an adjustable timer means having means to send an intermittant signal and a normally closed skim collection outlet valve means which is operatively connected to said timer means to recieve said intermittant signal and opens in response to said intermittent signal received from said timer.
 5. The apparatus of claim 1, wherein said means for introducing the liquid comprise at least one conduit connected
 6. An apparatus for removing suspended matter from a liquid, comprising;a substantially cylindrical vertically oriented vessel having an interior chamber therein adapted to receive a flow of liquid having suspended matter therein; an annular separation wall means mounted in the vessel transversely to a vertical axis of the vessel for separating a lower gasification chamber from the remainder of the interior chamber, said separation wall means having a central opening therein and being attached to a continuous side wall of the vessel about the circumference thereof; a degassification chamber formed above said separation wall means in fluid communication with the gasification chamber through said central opening; means for introducing the flow of liquid into the gasification chamber comprising a primary liquid distribution means located adjacent a bottom of the vessel and a secondary liquid distribution means having an independent outlet within the vessel at a level slightly above said primary liquid distribution means; means for introducing a flow of gas in the gasification chamber for attracting the suspended matter and for carrying the suspended matter upwardly to the degasification chamber, said gas introducing means comprising an eductor means having an outlet at substantially same level as an outlet of said secondary liquid distribution means within the vessel; means for concentrating the suspended matter extending vertically through at least a portion of the degassification chamber, said means for concentrating comprising a vertical funnel having a diameter substantially smaller than diameter of the interior chamber, said funnel being attached to said separation wall means and circumferentially surrounding said opening in the separation wall means; a skim collection means for collecting the suspended matter in the upper portion of the vessel and delivering skim outside of the vessel, said skim collection means being positioned at a level above said concentration means; means for removing treated liquid from the vessel positioned in a lower part of the degasification chamber; and,a means for controlling a volume of skim collection comprising a liquid level controller means operatively connected to the upper portion of the vessel, said liquid level control means having means to transmits a signal to a normally open control valve means, said control valve means operatively connected to the means for removing treated liquid from the vessel and an adjustable timer means operatively connected to said control valve means for intermittently interrupting said signal from said liquid level controller means to slightly increase said volume of liquid contained within the vessel by throttling or closing said control valve means, so as to raise a level of liquid and allow skimming through said skim collection means.
 7. The apparatus of claim 6, further comprising a treated water recirculation means fluidly connecting the degasification chamber with said means for introducing liquid into the vessel.
 8. The apparatus of claim 7, wherein said liquid recirculation means is provided with a check valve means mounted upstream from a point of connection of said liquid recirculation means to said liquid introducing means, said check valve means opening when a value of pressure in said recirculation line is greater than a value of pressure in said liquid introducing means.
 9. The apparatus of claim 6, further comprising a gas recirculation means fluidly connecting the upper portion of the degasification chamber with said means for introducing the flow of gas into the gasification chamber.
 10. The apparatus of claim 6, wherein said means for introducing liquid comprise a means of bypassing fluidly connected to said primary and said secondary liquid distribution means and mounted upstream from said outlet of said secondary liquid distribution means.
 11. The apparatus of claim 6, wherein said secondary liquid distribution means comprise a pressure control means operatively connected with said means for bypassing and said pressure control means functions to control a predetermined flow of liquid through said secondary liquid distribution outlet means and divert any excess liquid through said primary liquid distribution means.
 12. An apparatus for removing suspended matter from a liquid, comprising;a substantially cylindrical vertically oriented vessel having an interior chamber therein adapted to receive a flow of liquid having suspended matter therein; an annular separation wall means mounted in the vessel transversely to a vertical axis of the vessel for separating a lower gasification chamber from the remainder of the interior chamber, said separation wall means having a central opening therein and being attached to a continuous side wall of the vessel about the circumference thereof; a degassification chamber formed above said separation wall means in fluid communication with the gasification chamber through said central opening; means for introducing the flow of liquid into the gasification chamber comprising a primary liquid distribution means located adjacent a bottom of the vessel and a secondary liquid distribution means having an independent outlet within the vessel at a level slightly above said primary liquid distribution means; means for introducing a flow of gas in the gasification chamber for attracting the suspended matter and for carrying the suspended matter upwardly to the degasification chamber, said gas introducing means comprising an eductor means having an outlet at substantially same level as an outlet of said secondary liquid distribution means within the vessel; means for concentrating the suspended matter extending vertically through at least a portion of the degassification chamber, said means for concentrating comprising a vertical funnel having a diameter substantially smaller than diameter of the interior chamber, said funnel being attached to said separation wall means and circumferentially surrounding said opening in the separation wall means; a skim collection means for collecting the suspended matter in the upper portion of the vessel and delivering skim outside of the vessel, said skim collection means being positioned at a level above said concentration means; means for removing treated liquid from the vessel positioned in a lower part of the degassification chamber; and, a means for controlling a volume of skim collection comprise a liquid level controller operatively connected with the upper portion of the vessel and having means to transmit a signal, treated liquid outlet control valve means operatively connected to receive said signal from said liquid level controller, an adjustable timer means, connected to a normally closed skim collection outlet means and having means to transmit an intermittent signal to said normally closed skim collection outlet means which opens in response to said intermittent signal received from said timer means.
 13. An apparatus for removing suspended matter from a liquid, comprising:a substantially cylindrical vertically oriented vessel having an interior chamber therein adapted to receive a flow of liquid having suspended matter therein; an annular separation wall means mounted in the vessel transversely to a vertical axis of the vessel for separating a lower gasification chamber from the remainder of the interior chamber, said separation wall means having a central opening therein and being attached to a continuous side wall of the vessel about the circumference thereof; a degassification chamber formed above said separation wall means in fluid communication with the gasification chamber through said central opening; means for introducing the flow of liquid into the gasification chamber comprising a primary liquid distribution means located adjacent a bottom of the vessel and a secondary liquid distribution means having an independent outlet within the vessel at a level slightly above said primary liquid distribution means; means for introducing a flow of gas in the gasification chamber for attracting the suspended matter and for carrying the suspended matter upwardly to the degasification chamber, said gas introducing means comprising an eductor means having an outlet at substantially same level as an outlet of said secondary liquid distribution means within the vessel; means for concentrating the suspended matter extending vertically through at least a portion of the degassification chamber, said means for concentrating comprising a vertical funnel having a diameter substantially smaller than diameter of the interior chamber, said funnel being attached to said separation wall means and circumferentially surrounding said opening in the separation wall means; a skim collection means for collecting the suspended matter in the upper portion of the vessel and delivering skim outside of the vessel said skim collection means being positioned at a level above said concentration means; means for removing treated liquid from the vessel positioned in a lower part of the degassification chamber; and, a means for controlling a volume of skim collection comprising a normally open treated liquid outlet valve means operatively connected to said treated liquid removing means, an adjustable timer means operatively connected to said valve means and having means to send intermittent signals to said valve means causing said valve means to close, and a normally open, vertically adjustable nozzle means connected to said treated liquid outlet means and, for maintaining a predetermined volume of liquid in the vessel. 